QTc Calculator – ClinicalToolsDEV

Inputs

QRS Type

Select based on QRS duration. Wide QRS mode will prompt for QRS and gender.

Heart Rate (bpm)

Measured ventricular rate in beats per minute.

QT Interval (ms)

Onset of QRS to end of T wave, in milliseconds.

QRS Duration (ms)

Required for wide QRS (e.g., BBB, paced rhythm, IVCD).

Gender (for Rautaharju wide)

Male Female

Used only for wide QRS Rautaharju QTc. Narrow QRS modes use a sex-neutral Rautaharju variant.

Enter values and click "Calculate QTc" to view results.

Show QTc formulas

All formulas assume QT and QRS in milliseconds and RR in seconds.

Bazett (Bazett 1920)
QTc = QT / √RR
Fridericia (Fridericia 1920)
QTc = QT / RR^1/3
Framingham (Sagie et al. 1992)
QTc = QT + 154 × (1 − RR)
Hodges (Hodges et al. 1983)
QTc = QT + 1.75 × [(60 / RR) − 60]
Rautaharju (HR-based, narrow QRS)
QTc = QT × (120 + HR) / 180
Bogossian method (wide QRS)
QT_m = QT − 0.5 × QRS
QTc_Fridericia = QT_m / RR^1/3
Rautaharju wide-QRS (QT8)
QTc = QT − 155 × (60 / HR − 1) − 0.93 × (QRS − 139) + k
k = −22 ms (men), k = −34 ms (women)

Show references

Bazett HC. An analysis of the time-relations of electrocardiograms. Heart. 1920;7:353–70.
Fridericia LS. Die Systolendauer im Elektrokardiogramm bei normalen Menschen und bei Herzkranken. Acta Med Scand. 1920;53:469–486. (Translated reprint: Ann Noninvasive Electrocardiol. 2003;8(4):343–51.)
Sagie A, Larson MG, Goldberg RJ, Bengtson JR, Levy D. An improved method for adjusting the QT interval for heart rate (the Framingham Heart Study). Am J Cardiol. 1992;70(7):797–801.
Hodges MS, Salerno D, Erlinen D. Bazett's QT correction reviewed: evidence that a linear QT correction for heart rate is better. J Am Coll Cardiol. 1983;1:694.
Rautaharju PM, Mason JW, Akiyama T. New age- and sex-specific criteria for QT prolongation based on rate correction formulas that minimize bias at the upper normal limits. Int J Cardiol. 2014;174:535–40.
Rautaharju PM, Zhang ZM. Linearly scaled, rate-invariant normal limits for QT interval: eight decades of incorrect application of power functions. J Cardiovasc Electrophysiol. 2002;13:1211–1218.

Any critical values, red flags, or important notes will appear here.